Pressure gauge



J. WAHL PRESSURE GAUGE Jan. 1 7, 1933.

Fil'ed March 5. 1950 Ssss .i l

INVENTOR M,

By Attorneys,

Patented Jan. 17, 1933 UNITED STATES PATENT OFFICE JOHN WAHL, on Rossmann, NEW YORK,

ASSIGNOR TO A. SCHRADERS SON, INCOR- PORATED, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK PRESSURE GAUGE Application filed March 5,

The present invention relates to pressure gauges, and more particularly to tire pressure gauges of 'the telescoping indicating member type, and aims to provide certain improvements therein.

In ascertaining tire pressures according to the present practice, two separate gauges are employed; one for the relatively low pressures to which balloon tires are inflated, and another for the higher pressures to which the so-called high pressure tires are inflated. Ot course the motorist naturally provides himself with a gauge having the pressure range of the type of tire on his, car. At service stations, however, the op erator must rely on two separate gauges,

which not only necessitates carryingA two gauges on his person, but often provokes veXation when he withdraws the wrong gauge to take a tire'pressure reading.

According to the present invention I provide a pressure gauge which eliminates the need and inconvenience of using two separate gauges. This gauge may be termed a service station gauge, as it is capable of measuring both the relatively low pressures used in balloon tires, and the higher pressures employed in high pressure tires, with the same vdegree of accuracy now realized with separate gauges, and is usable in pre- ,Cisely the same manner as the conventional tire pressure gauge.

According to the present invention I provide a tire pressure gauge of the telescoping indicating member type which comprises a tubular casing, an indicating member telescoping with said casing, and pressure responsive element movable in said casing and adapted when subjected to fluid pressure to move the indicatingmemberto indicating position, said indicating member having indicia embracing a plurality of pressure ranges and a spring for resisting movement of the pressure responsive means when subjected to fluid pres-- sure` the resistance of said spring up to a certain point governing one pressure range of the gauge, and the resistance beyond said point governing a second pressure range. The invention also embodies other -features 1930. Serial N0. 433,372.

of novelt which will be hereinafter more fully described.

A preferred embodiment of my invention is shown in the accompanying drawing, wherein Figure l is a longitudinal section through a gauge embodying my invention, the presson foot of the gauge being shown in elevation.

Fig. 2 is a view similar to Fig. l, showing the indicating member in indicating posi-y tion.

j Fig 3 is an elevation of the gauge spring in-normal condition.

Fig. 4 is a side elevation partly in section of the indicating member of the gauge.

Fig. 5 is a fractional longitudinal section on an enlarged scale, showing a detail of the invention.

Fig. 6 is a transverse section taken substantially along the plane of the line 6-6 of Fig. l.

Fig. 7 is a fractional section on an enlarged scale of another detail of the invention.

Referringto the drawing let A indicate a cylindrical casing. which, for the purpose of economy may be made of tubular stock, one end of said casing being flanged inwardly to provide an overhanging lip a, and at its opposite end is externally screw-threaded, as shown at a', and engages within an internally screw-threaded bushing b on a fit-ting B which is provided with a conventional tire press-on seat and deflating pin (not shown) fitted within the foot portion for engaging and forming a leak-tight joint with the top of a tire valve when the foot portion is applied thereto. At the top or rear of the foot portion b there is provided a teat or projection b2, which may function as a tire deflating pin when it is desired to vent air from a tire.

Within the casing A there is provided a pressure responsive means or piston C which carries on its underside a/cupped, compressible packing c which is adapted tofengage the inner wall of the casing and provide a leak-tight seal therewith, and on its upper side is provided with a reduced cylindrical projection c for engagement with the bottom wall d of an enlargement d' carried by"y thei gauge is designed for dual use on both balloon lower end of the pressure indicating member and so-called high pressure tires, and to renor bar D. ,Y der said gauge adaptable for such dual pur- To always insure a proper leak-tight conpose I rovide a novel construction of spring 5 tact between the packing c and the inner wall means or resisting movement of the pressure 70 of the casin A, I provide within the casing Aresponsive member, said spring means being and prefera ly at the inner end thereof, and so constructed that when subjected to deforas herein shown in contact withrthe base b3 of mation up to a certain point said deformation the bushing b, a disk-like member E which will be proportional to one pressure range of l0 is clamped against said base by the inner the gauge; and when subjected to further 75 end of the casingA engaging-around a shouldeformationpsuch deformation will be proder e .of the disk E. The disk E is formed lportional to another pressure range of the on its upper face with a circumferential rib gauge. The spring construction is also such e', the outer face o'f which tapers inwardly that unit pressure deformation of the spring l toward its Outer end to provide a conical Within each of its pressure ranges will be 80 surface e which is adapted to engage the equal, but unequal in the diiierent pressure inner' wall of the. packing c and press the ranges. This permits of the calibration of same outwardly1 as said packing rides over the gauge bar intopressure ranges, or, in and seats against said conical seat when other Words, permits` the gauge bar for one I 2 pressed ,thereagainst by the force of the pressure range to bb equally divided and 85 1 gauge loading spring F. A central opening marked in a certain arithmetical progressi on, e' is provided in the base of the diskE to and another portion or pressure range in a permit the passage of air from a tire into the different arithmetical prOgIeSSiOil.

gauge toact upon the piston therein, TheI spring F, by means of which I accom- Loosely positioned within the casing at its plisli;the advantages set forth in the preced- 90 top is a cap closure element or disk G having ing paragraph, .is of the helical coil type a diameter slightly greater than the internal V,C'rmed of a Wire of uniform cross-section diameter of the inturned lip a so that the coiled into convolutions of uniform diameter, y

disk G cannot pass therethrough, Said disk which convolutions, for approximately one- 80 is fonnod with an opening g of similar conhalf the length of the spring f, are more close- 95 tour with the gauge bar D and through which ly' spaced apart than in the other half f with the latter is adapted to freely move, saidl the Convohitions in the portion f equally opening g being anked by a. struoknip hongo spaced apart and those in the portion f also which Servesv as a guide for the gauge'bar equally spaced apart, but a distance differ and an aid for reading the. indicia thereon ent from the spacing in the portion f. Under 100 Also positioned within the easing below the Compression .the entire Spring F will u nidisk G is a second disk H which is cupped fOlmly Weld WOPOI'IUUULH)7 t0 the PPhQ, to provide a shallow recess, as best'shown in PI'QSSUIQ A t a predetermined pressure, in Fig, 5 Within said oup'is positioned a Split. the present instance 60 lbs. per square inch,

do sp1-ing ring h having 9, Contour which will the convolutions of the portion f will be coin- 105 revent its passage through the opening in pressed into completely abutting relation so the disk G and which is adapted to frictionthat upon the spring being subaiected to adolly engage tho side edges of the gauge bar ditional pressure, only .the portion f', which or indicating member D to hold the same in 1S, already under @Onslderable compression, e

,my positionto whiohsaid gmigohar is pro. will be brought into active play. Because 110 jected by the 'piston after the said piston has of thisE direct proportional relationship berotui-nod to its normal oizoro position. f tween the pressure and lthe compression of From the foregoing description it will be he SPI'mg, the gauge ha? D CM1 be Clblflted seen that the spring F normally maintains m130 the t-WO Pressure ranges, namely dz,

the piston in zero position and the closure from Zero t0 60, and, (Z3, from GQ t0 160- 115 cap G at the outer end of the casing, and as ObVlOllS-ly th@ {U01/115mg 0f the, dlfferently the disks G and H are loosely positioned spaced convolutions of the spring may be within the casing and h eld against'the indlffelfently arranged Without affecting itSpturned lip a merely by spring pressure`- it. eration, but as a practicable proposition it will be apparent that said disks will he free is easier to forma spring as shown in the 121 to rotate within Vtho casing when@ gauge baidrawing. For preventing movement ofthe is rotated. A swivel connection between the gauge bar thrOugh the top of the casing bev auge bar and the casing is thus provided, vond its pressure indicating range, it is The detailed description of the gauge as thus formed with a SOP 01' abutment d* by de- 00 far given is substantially the same as that pressing a portion of' the metal of the gauge 12 disclosed in vmy application Serial No, bar out of its normal planes, as best shown 399,200, filed October 12, 1929, and upon in Figs. 1 and 4. l which the present invention is an.improve Repeated movement of the gauge bar D ment. through the top of the casing` in which move- C5 According' to the present invention the ment it must pass through the opening g in 1E time. will Wear the disk G and through the opening 7L in the disk H, as Well as have sliding frictional contact with the spring L, in the course of upon the side edgesl of the gauge bar Dto roughen the same thereb increasing the resistance to movement o the piston and apt to introduce a source of error in the indicated pressure. Although means have been provided for compensating such errors in gauges, I propose to eliminate this source of error, and accordingly introduce into the gauge casing and preferably Within the cup I-I, lubricating means in the nature of an absorbent or porous disk h2 which is saturated with a lubricant such as oil or graphite. The disk k2 is provided with an opening through Which the gauge bar D passes, the Walls of said opening contacting' with Ithe outer Walls of the indicating member. j

For providing a leak-tight seal between the inner end of the casing AA with the fitting b and supplementing the engagement between the end of said casing A With the disk E, I form the fitting b with an internal annular groove b4 above the internal threads therein, and provide Within said groove a compressible packing b5, the internal diameter of which is slightly smaller than the external diameter of the casing A, so that when the latter is" screw-threaded into the fitting b the packing b5 Will be compressed l into engagement with the threaded end a of the casing to provide a leak-tight joint.

While I have shown and described a preferred embodiment of my invention I do not wish to be limited to the details of construction disclosed, since the same may be modified Without departing from the spirit of the invention.V i

What I claim is:

1. A pressure gauge comprising a casing, pressure responsive means Within said casing,

.pressure indicating means operable by the movement of the pressure responsive means and means in communication with the interior of the casing for connection with a source of fluid pressure to be gauged, said pressure indicating means having indicia ,embracing a plurality of pressure ranges, and a helical spring for resisting movement of the pressure responsive means Whensubjected to fluid pressure, the convolutions of the spring fori different portions of its length being dill'erentlyspaced.

2. A pressure gauge comprising a casing, pressure responsive means Within said casing, pressure indicating means operable by the movement of the pressure responsive means and means in communication with the interior of the casing for connection With a source of fluid pressure to be gauged, said pressure indicating means having indicia embracing a plurality of pressure ranges, and a helical spring for resisting movement of the pressure responsive means when subjected to Huid pressure, the convolutions of the s ring for approximately one-half its lengt being more closely spaced than for the other half. v

3. A pressure gauge comprising an elongate casing having ai fluid pressure inlet at one end, pressure responsive means within said casing, pressure indicating means operable by the outward movement of the pressure responsive means, said indicating means having indicia embracing a plurality of pressure ranges for the gauge, and a helical compression spring within said casing for resisting movement of the pressure responsive means when subjected to fluid pressure, the convolutions of the spring for different portions of its length being more closely spaced in one'portion than in another, at least one of said portions of the spring upon being subjected to the maximum pressure of the first pressure range ofthe gauge being adapted to become completely compressed and providean abutment for the adjacent portion of the spring. l

4. A pressure gauge comprising an elongate casing having a lluid pressure inlet at one end, pressure responsive means within 4 said casing, pressure indicating means operable by the outward movement of the pressure responsive means, said indicating means having indicia embracing a plurality of pressure ranges for the gauge, and a helical compression spring within said casing for resisting movement of the pressure responsive means when subjected to fluid pressure, the convolutions of the spring for different p0rtions of its length being more closely spaced in one portion than in another but equally spaced apart in eac-h portion, the portion of sa1d spring having the most closely spaced convolutions, upon being subjected to the maximum pressure of the first pressure range of the gauge, being adapted to become completely compressed and provide an abutment for the next portion of the spring;

5. A pressure gauge comprising lan elonlgate casing having a fluid pressure inlet at o'ne end, pressure responsive means Within said casing, pressure indicating means operable by the outward movementof the pressure responsive means, said indicating means having 1nd1cia embracing a plurality of pressure an article of manufacture, a helical i and having its convolutions for different portions of the length of the spring more closely spaced apart than in another, the convolutions in any portion being equally spaced L'5 from each other.

7. As an article of manufacture, a helical.

coil spring formed of Wire of uniform crosssection and convolutions of uniform diameter, and havin its convolutions for approxim matel one-hal its length more closely spaced than or the other half with the convolutions in each half equally spaced apart.

8. A pressure gauge for pneumatic tires or the like, comprising an elongate casing K having a fluid pressure i let at one end and an opening in its other end, pressure responsive means movable in said casing, an indicating member movable by said pressure responsive means through the opening in the @0i end of the casing, means for guiding said indicating member through said opening and lubricating means held Within said casing below the open end thereof for engaging the walls of the indicating member.

9. A pressure gauge for pneumatic tires or the like, comprising an elongate casing having a fluid pressure inlet at one end and an opening in its other end2 pressure respon sive means movable in said casing, a non- 3'Jcircular indicating member movable by said pressure responsive means through the opening in the end of the casing, means for guiding saidindic'ating member throuvh said opening anda lubricated Wiper held Within the casing ibelow the open end thereof in contacting position with the Wall of the indicating member. 10., A pressure gauge for pneumatic tires orthe like, comprising a cylindrical casing having a fluid pressure inlet at one end and oan opening at its other end Whereat it is formed with an inwardly overhanging lip, a piston movable in. said casing, an indicating member movable by but disconnected from said piston, a circular closure cap loosely positioned withinthe opening formed by the overhanging lip and having' an opening corresponding to the cross-sectional form of the indicating member which passes therethrough, a disk adjacent the closure cap provided with vresilient means in engagement vvith the edges of the indicating member and adapted to hold said member at any position to which it is moved by the piston, a disk'of lubricant p containing material having an opening through which the indicating ineinber passes and with which the outer Wall of the indicating member engages supported below the closure cap, and a spring Within the casing bearing at one end against thepiston 'and at its other end against the disk adjacent the closure cap. g

In Witness whereof, I have hereunto signed vmy name. G JOHN WAHL. 

